All posts tagged "Astronomy"

01/20/2012

In snowy states, it can be hard to sleep in winter when there’s a full moon, because the glow coming off the snow lights up the outside world. The brightness behind my curtains on a snow-covered, full-moon night is comparable to my neighbors leaving their garage light on during a summer night during new moon.

Fortunately for my beauty rest, a new moon is on the way. January’s new moon occurs on Monday the 23rd, assuring me of darkness out the window, if cloud cover hasn’t already taken care of that for me.

Many people find the moon most interesting when it is rising in the east in full phase, often showing a yellow or orange hue and looking gargantuan when compared with earthly objects. While this is undeniably a pretty sight, I find the moon most intriguing on the nights following new moon, as the slender crescent creeps into sunset skies and slowly reveals more of its lit face.

The fourth week of January will be a great time to watch the moon emerge as a crescent and wax toward its first quarter phase, on January 31. The sunshine hitting the edge of the moon is a lovely sight, but what also draws the eye is the faint light coming from the night portion of the moon. This is called Earthshine, because light from the sun is hitting Earth and reflecting into space, hitting the dark side of the moon and then reflecting back toward us. The degree of brightness of Earthshine is influenced by what is happening on Earth; for example, if the side of Earth that the sunlight is reflecting off is especially cloudy, it will cause more light to be reflected and light up the dark side of the moon a bit more.

Another factor that figures into the scenario of the light on both snow and the moon is their albedo. Albedo refers to the amount of reflectivity an object has. Fresh snow has one of the highest albedos, with 80 to 95 percent of the light that hits the snow reflected back. The moon, while it looks white and bright (at least outside of the mare regions), is actually not bright at all. It’s just that the only thing we really can compare it to is the blackness of space. But in actuality, the surface of the moon is quite dark and only reflects back 12 percent of the light that hits it.

Look this coming week for the dark side of the moon lit by Earthshine. You may even be able to make out a number of the dark mare under the lunar night. Earthshine is sometimes poetically referred to as seeing the old moon in the new moon’s arms.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

01/13/2012

Easy-to-spot Venus is the key to finding Neptune. Credit: John Chumack

Neptune is the most difficult planet for observers to check off their list. It is faint, at only magnitude 8.0, making it nearly impossible to distinguish from thousands of background stars. But every once in a while the farthest planet from the Sun drifts past another planet as seen from Earth. Using the closer and brighter planet as a guide, we then have a chance to spot the elusive Neptune.

Friday, January 13, 2012, is one such occasion. Venus, the brightest object in the night sky (the moon won’t be up) is easy to find as it glows brilliantly in the west after sunset. Using a pair of binoculars or a telescope, aim them at Venus. Just a little more than one degree to Venus’s right is Neptune. On this night, Neptune isn’t the closest point of light to Venus. Just below Venus is a star that shines at magnitude 6.9, and below that is an even brighter star at magnitude 4.2, Iota Aquarii. These distractions can actually help you spot Neptune.

If what you see when looking through the eyepiece is bright Venus with a small dot above it and a slightly brighter star above that, then you know that your telescope gives you an inverted view so you actually need to be looking to Venus’s left to find Neptune. Iota Aquarii is almost one degree away from Venus, so measure approximately that distance to Venus’s side (right or left depending on whether or not your view is inverted) to find Neptune.

Depending on how good your eyes and equipment are, you may see that Neptune has a bluish color and appears to be more of a disk and not pointlike, as the distant stars appear.

If your skies are cloudy on Friday, you can try again on Saturday, although Venus will already have moved farther away from Neptune, making their separation two degrees. Neptune will be to the lower right of Venus. Try looking just to Venus’s right for a trio of stars, then look just below them for one lonely point of light; this is Neptune.

Venus continues to climb upward away from Neptune each night. By February, Venus will be approaching the second most difficult planet to bag, Uranus. The Venus-Uranus encounter will be a much closer one, with the two planets appearing just 18 arcminutes, or less than a third of a degree, apart.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

01/06/2012

Some leftover sparkles appear to be hanging in the sky from the New Year’s fireworks. Venus is now so bright in the southwest after sunset that it gets mistaken for an airplane. Jupiter is high in the south, outshining all the stars in its vicinity. Through a telescope you can watch the phase of Venus slowly shrink over the coming weeks and track Jupiter’s moons as they orbit the giant planet.

The most difficult planet to see in the solar system is Neptune (at least since Pluto got demoted), but for one night this month it will be a bit easier. At magnitude 8.0, you’ll need some optical aid to spot it, but because it lies next to Venus, it will be easy to pick out from the myriad of background stars.

On January 13, Venus will pass approximately one degree to the left of Neptune. Aim a telescope toward the easy target of Venus. Look for the “star” that is just to Venus’s right (although most telescopes give an inverted view, therefore Neptune will be to Venus’s left). Once you’ve spotted it through a telescope, you can see how difficult it would be to pinpoint it in a field of stars without any bright guide to lead the way.

If you don’t have a telescope, give it a try in binoculars. The hardest part with binoculars is holding them still so the dim point of light doesn’t jump around. Try reclining in a lounge chair so that you can set your elbows on the armrests. Neptune should have a bit of a bluish color to it.

For more observing information for January through March 2012, see the SkyGuide at AstronomyToday.com.

Photo credit: Kelly Whitt. Picture of Venus and the Moon was taken in February 2009.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

12/22/2011

Even though owning a telescope will suddenly open up unseen worlds in the night sky, from clusters to galaxies to nebulae, the best sight will always be the moon. This is especially true for beginners because the moon is easy to find and the detail never disappoints.

For anyone who received a telescope over Christmas, the moon will be up in the early evenings for the rest of the year, hanging around a bit longer each night and growing fuller as it comes out of its most recent new phase, which was on Christmas Eve.

One of the very noticeable features on the moon when it is about 3 days old, which it will be on the 27th, is the large dark circle in the upper right area. This is Mare Crisium, or the Sea of Crises, one of the old lava-filled basins distinguishable by its dark hue. Each following night as more of the moon is lit, you will see more craters and mare appear. The large one below Mare Crisium is Mare Fedcunditatis, or the Sea of Fertility, and to the upper left of it separated by a thin white ridge, visible around December 30 this month, is Mare Tranquillitatis, or the Sea of Tranquility. This mare is famous for being the landing site of Apollo 11, the location of where humans first stepped on the moon.

A couple notable bright spots to point out on the moon over the coming week are three white craters. Near the bottom right edge of Mare Fecunditatis is a white circular crater known as Langrenus. Through a telescope you can see the central peaks on the crater's floor. To Langrenus and Mare Fecunditatis's lower left are two bright white craters close together. These two craters are Stevinus (upper left crater) and Furnerius (lower right crater). Both craters have a prominent ray system of material that was ejected during the impacts that created them long ago. See if you can trace the chain of craters that leads from Stevinus and Furnerius back up to Langrenus.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

12/16/2011

A half-lit Earth as seen by the Apollo 8 astronauts on the moon. Credit: NASA

The moon is not the only solar system object to display phases. Planets can also show a phase, depending on the positions of the planet, the sun, and the Earthly viewer. Even the Earth has phases, as was witnessed by astronauts on the moon.

Venus is one of the easiest planets to observe phases in because it's close to Earth and can be viewed with just a pair of binoculars. Venus and Earth are both spinning along in their orbits, but Venus's forward motion is a bit faster. At the moment Venus is emerging from around the corner of the sun and coming into better view for us on Earth. You can look for the bright point of light in the southwest after sunset to find it. With the sun is positioned between us and Venus, the Goddess of Love exhibits a larger, gibbous phase, as it is now. As Venus catches up with us (being on an inner orbit) and pulls closer to us, its phase will shrink. But even though its phase is shrinking, its overall size, or angular diameter, will grow larger as it gets closer, and the planet will appear brighter.

12/08/2011

A total lunar eclipse occurs when a full moon lines up with Earth and the sun such that the moon enters into Earth's shadow. Who gets to view the eclipse is determined by what part of Earth is facing the moon at the right time. On the morning of Saturday, December 10, 2011, a lunar eclipse occurs that is situated perfectly for Asia but a bit sketchy for those of us in North America. The partial phase of the lunar eclipse begins at 12:45 UT, with the total phase beginning at 14:06 UT. Complete totality lasts for just under an hour, ending at 14:57 UT. Then the partial phase repeats as the moon slips back out of Earth’s shadow, with the event concluding at 16:17 UT.

Convert Universal Time to your local time to know when you should be looking. For those on the West Coast, that means you will have the best chance to see it. The total eclipse begins at 6:06 a.m. PST, 7:06 a.m. MST, 8:06 a.m. CST, and 9:06 a.m. EST. The problem with these times is that when the total lunar eclipse begins for those on the East Coast, the moon will already have set. So, for example, in Denver the moon sets at 7:12 a.m., allowing for observers to see all the partial phase but just a peek of the total phase.

12/02/2011

December hosts more hours of darkness than any other month. This is because the solstice occurs just after midmonth. On December 21 for those in the Central Time Zone and to the west and just after midnight on December 22 for those in the Eastern Time Zone, the solstice occurs. This is the moment that Earth’s northern axis tilts as far away from the sun as it gets.

All these extra hours of darkness, not to mention the coming cold of winter, makes people want to curl up inside by a fire and read a good book. But if you can brave the cold dark nights, you can see some beautiful astronomical delights.

The two brightest planets, Jupiter and Venus, are taking up residence in the evening sky. They are not hard to miss. Look for an unmistakably bright point of light in the west after sunset; that will be Venus. The bright beacon climbing high in the east-southeast is Jupiter.

The winter constellations, most notably the grand Orion, are also appearing in the east during mid-evening. The full moon of December is called the Cold Moon, which occurs on December 10 this year. A total lunar eclipse will also occur on that date, which will require early morning viewing for those of us in North America. See more about the eclipse in next week’s blog.

Two annual meteor showers occur in December, with the Geminids on December 13 being one of the best of the year with 80 meteors an hour possible. A waning moon will interfere with the show, however. The Ursids is the second shower, occurring on December 22, but it only provides about 9 meteors an hour at maximum.

Annual meteor showers are created by Earth passing through the debris trail of comets. But the Geminids is unusual in that the space object that left behind the debris trail was an asteroid known as 3200 Phaethon. Recent research has bolstered the evidence that Phaethon is related to asteroid belt inhabitants such as Pallas, one of the largest known asteroids. Phaethon’s composition is significantly similar, but Phaethon is a rebellious child, sometimes acting comet-like.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

11/25/2011

One question I get asked frequently, especially in the weeks before Christmas, is what is a good starter telescope to buy? Many people who ask this question have already glimpsed telescopes for sale at the big box stores and are looking for a price tag of $200 and under. The telescopes that you find in these stores that promise amazing sights (see unrealistic photos on the box they come in) are not worth your time or money. The small sizes won't give you views better than most binoculars, the mounts are rickety and often the scope is not assembled well and little support is provided.

Because there generally aren’t stores around that offer a wide range and selection of good quality telescopes, your best bet is Internet shopping. Three well-known companies that sell an assortment of equipment worth checking out are Meade, Orion, and Celestron, although there are certainly many other brands that will also provide you with a quality telescope.

There are a lot of factors to consider when buying a telescope, such as whether you want a refractor or reflector, what size to buy, how stable is the mount, can it be easily transported to my viewing site, and so forth. Not to mention how much money you have to spend. The answers to these questions will differ depending on the person, which is why it makes it hard to give general recommendations.

One additional factor that has become very popular over the past decade is the GOTO telescope. This type of telescope allows you to align with a couple of bright stars and then you use the keypad to punch in what you want to see and the telescope motors its way to your desired object. GOTO telescopes have positive and negative attributes. A few negatives are that they are definitely pricier (and it’s getting harder to find scopes without the GOTO feature) and they don't really help you to learn the sky. A benefit of a GOTO scope is that if you’re efficient at aligning, you can maximize your time at the scope by having it do the star hopping for you.

Some telescopes are sold without mounts, as "tabletop" versions, which helps to cut down on the price for those just starting out, but be sure you have a sturdy place to view from. A shaky table or tripod will ruin anything that could have been gained with your inexpensive scope.

Dobsonian telescopes are one of my favorite types of scopes for those starting out, because you can get a decent-sized scope (4.5-inch, 6-inch, or 8-inch) for under $500. The simple design makes it the best value and easy to use for beginners. Although if you’re an apartment dweller who has to load up your telescope and drive to a dark-sky site every time you want to observe, a 4.5-inch reflector may be more practical.

One caveat about buying a telescope for Christmas: depending on where you live, that telescope may not see much use until it’s warm out. While a telescope always sounds like a fabulous Christmas present, the truth is, for those of us in the northern climes, it’s just not that pleasant to stand outside on a below-freezing night and fiddle with eyepieces and try to find your target in the scope. First timers can get a bit disillusioned as they shiver and try to get a hang of their new gift. Fortunately this year, the week after Christmas features a crescent moon visible just after sunset, allowing new telescope users to go out early in the evening and train their scopes on the easiest target in the heavens.

Despite awesome claims on some telescope boxes, you won't see the Christmas Tree Cluster and Cone Nebula in this picture through any amateur scope. Photo credit: ESO.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

11/18/2011

The constellation Pisces rises in the east this weekend after sunset. The planet Jupiter will be to the constellation’s lower left. Credit: Till Credner

Most people who have heard of Pisces think of it as a sign of the Zodiac for those who have birthdays in late winter. But Pisces is actually a constellation known as The Fish that is easy to spot in the eastern sky on fall nights once you know where to look.

Pisces is made even easier than usual due to bright Jupiter just to the left of the constellation. The stars forming a large V to Jupiter’s right and above are part of Pisces, and when you run into the Great Square of Pegasus above it, you’ve gone too far. The most noticeable part of Pisces is called the Circlet. The Circlet is a generally round shaped collection of stars at the southern end of the constellation’s V shape.

Pisces is indeed a constellation of the Zodiac, which means that it lies along the plane of the solar system where planets and the moon and sun may pass. Thus, Jupiter is just across the border in Aries these days. Jupiter will pass into Pisces at the beginning of next month. The moon also spent four days traveling the length of Pisces earlier in November and will do so again December 2-5, and on December 6 it will lie just beside Jupiter as Jupiter moves into Pisces and the moon passes it going the other direction, into Aries.

Pisces is the 14th largest of all the constellations. It contains one Messier object, M74, a dim magnitude-10 spiral galaxy. M74 is one-and-a-half degrees east-northeast of Eta Piscium, but requires a large scope, dark site, and lots of patience to see.

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

11/11/2011

This photo is a good illustration of how much brighter planets can shine compared to stars. From top to bottom: the moon, Venus, Spica, and Jupiter. Credit: A. Pasten, A. Gomez, and NOAO/AURA/NSF

“Star light, star bright, first star I see tonight, wish I may, wish I might, have the wish I wish tonight.”

This childhood saying is one I got a lot of use out of over the years. When I was a kid and it started to get dark outside, I would walk out on my driveway and look out over the strawberry patch across the street from my house and watch the pink of sunset drain away in the west. Often, I would see a bright point of light there, and it was only after several minutes that other stars would begin to appear from the darkening blue of the night sky. I would whisper the nursery rhyme and then silently make my wish. Thinking back now, I can’t think of a single thing I ever wished for. And I’m certain those wishes seemed of vital importance to me at the time.

Ironically, the first “star” you see in the night sky is often not a star at all but a planet. When planets such as Venus and Jupiter are up in the night sky, they shine more brightly than any stars. As a kid as I looked west into the sunset and caught a glimpse of a brilliant point of light, chances are that it was the planet Venus. Venus has been absent from the evening sky for months, but it is returning again and will make itself better known over the coming weeks.

For those looking east after sunset, the brightest and therefore first point of light that emerges into twilight in this section of sky is Jupiter. Jupiter climbs higher each hour of the night and shines brightly at magnitude -2.9. Venus is the brightest of all pointlike objects in the night sky at magnitude -3.9. The brightest actual star in the sky is Sirius at magnitude -1.1, which currently does not rise until almost midnight — definitely not the first star you’ll see at this time of year.

If Venus and Jupiter were not in the sky, a handful of other stars of similar brightness would all be vying for the title of brightest. Beginning the night overhead but eventually setting in the west-northwest is the Summer Triangle, whose brightest star, Vega, shines at magnitude 0.0. Another star at about magnitude 0.0 sets in the west-northwest before Vega: Arcturus in the constellation Bootes. The twinkling star in the northeast is Capella at magnitude 0.1. As Orion rises, two other bright stars come into view, reddish Betelgeuse at magnitude 0.5 and bluish Rigel at magnitude 0.2.

Because I can’t remember them, I’m not sure if any of those wishes I made as a kid came true. But I have always loved writing and astronomy, and now that is what I do for work every day. I also ended up marrying my childhood sweetheart. So maybe my wishes did come true. Perhaps I should go out and wish upon the brightest star tonight ....

-- Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

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